|Aug 12, 2006, 09:09 PM|
New fast homebuilt - You can do it too if you miss your Projeti like I did !!!
This post is just an example to show that even those of us that don't really like building can produce some nice results with just a little motivation and good advice. Also starting from a proven airframe, and then making design and construction decisions to make the design your own and not just a copy.
Well, with the demise of the Projeti, I didn't know where to go next. I tried a Thunder Tiger Velocity and ended up giving it away after a few flights, so didn't have a convenient "high performance" plane with the same handling characteristics.
Soooooo, I decided to make my own and this is what I've come up with.
The airfoil thickness on this model is just 8%, so it had to be built strong with CNC cut foam cores, sheeted with vacuum bagged 1/16" balsa. There is a fair bit of uni-carbon under the skins. The elevons are kevlar hinged (kevlar was installed under the balsa skins), and have a layer of carbon for stiffness.
The L/E and tips are solid balsa, and the wing halves are joined with uni-carbon to a center keel sorta like the Great Planes Slinger. This keel integrates the fin that supports the motor. The motor cradle is 1 layer of Kevlar, two layers of unicarbon with the fibers oriented to be perpendicular to the motor can. I made the cradle longer to make room for the next motor (Aveox 27/26/1 and Phoenix 80). Span is a little more than a ProJeti, and area is up too.
With the normal gorilla grip methods the wing has proven to be very stiff in both the bending and twisting tests. Even the alevons are very stiff.
The fuse was carved from pink foam to be King Cat-ish. I've always loved the slick-ness of this fuse, so decided I'd do something similar. The battery tray is epoxied right to the uni-carbon that joins the wings. The fuselage carries no weight, it's just there for aerodynamics and dashing good looks.
CC Phoenix 25
APC 4.75x4.75 carbon
Current - 23A (measured with an Astro Whattmeter)
Watts - 200W (measured with an Astro Whattmeter)
rpm - 26,000
Static Thrust - 31.4oz
Pitch Peed - 115mph
Wingspan - 35.5"
Wing Area - 297.31"2
AUW - 22.7oz
Wing Loading - 10.99oz/ft2
Power loading is a confidence inspiring 140W/lb.
Here are a few preliminary pics, the air inlet has not yet been cut in these pictures. I truly hope this plane will help motivate basement builders who haven't scratch built in a while but still know how. This plane, start to finish was done in under two weeks !!
I will be maidening this plane tomorrow, wish be luck.
|Aug 13, 2006, 10:26 AM|
Due to an injury sustained early this morning I won't be maidening this plane until next weekend
I've completed the air intake and will post a few more photos including the interior battery arrangement.
|Aug 13, 2006, 12:11 PM|
Should be fast
Intend to share plans?
It seems to me the prop is the wrong way arround on this pic??
Success With the maiden.......
|Aug 13, 2006, 12:39 PM|
Thanks for thr kind words, I might actually get to maiden this afternoon.
I've double checked the prop and it is installed correctly.
As for plans, I'll share for sure. This plane is really more of a prototype to be honest, if it's successful I'm making molds for the wing and fuselage.
|Aug 14, 2006, 11:21 PM|
Yes, I did actually get to do the maiden, then 5 more flights after that. The model is fast, very smooth, and a piece of cake to land. It glides very, very well, and loafing around at 1/8 throttle the plane shows no nasty tendencies at all.
Mike (one post above) did my launches for me because of some damage I did to my right index finger, and he said it was just a light toss to get airborne
There was nobody else at the field with us so I wasn't able to get video, maybe next time.
I did do a few rolling circles and it's a dream to fly. I tested the wing a few times with some full elevator pull ups at full throttle and it took it just fine.
Dan (happy camper right now)
|Aug 15, 2006, 04:05 AM|
Thanks Hummingbird !
I'm very happy with this plane as it is. Now, time to work on the molds
I've added a foam piece right in front on the motor to help decrease drag, hope it helps.
Here are two more photos, one of the foam piece, one of the battery tray inside.
|Sep 20, 2006, 08:34 PM|
Let me know if you ever get the molds. I would love to buy just the wing, and then form my own stabs, and cowl.
|Sep 23, 2006, 10:48 AM|
Thanks Anthony, the prototype flies as well as I could have hoped. Very nice characteristics.
I've redesigned the fuselage to make that rear section a LOT more aerodynamic, but it's going to be a little while before the molds are ready. I'm also working on a pair of vacuum bagged 3 meter gliders and a Rutan/Amsoil Racer this winter, but you can expect stuff to be available by spring.
I'll be keeping this thread alive when the molding process continues.
|Sep 30, 2006, 01:01 AM|
The wing section is fully symmetrical. NACA008 at the root, transitioning to NACA009 at the tip. The prototype has 1 degree of washout, but I'm going to take that out.
I'm not sure how fast it is, but I estimate it's about 100mph. It's hard to tell without actually timing it or using radar.
|Sep 30, 2006, 03:51 PM|
If you take some video fo it flying within ten feet of you, we can do a doppler reading on it.
Also tell us the motor setup, prop and rpm's.
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